It is known that secure documents or instruments may be rendered less susceptible to forgery or counterfeiting by including security features in various forms within the body of the document. In fact, the security or integrity of a document or instrument will increase with the number of separate and distinct security features that it employs.
Many security papers and other items of value include a security device or element, such as a security thread, disposed on or within the document. The security device typically includes one or more security features, such as metallic, magnetic, x-ray absorbent, and/or luminescent security features, that serve to authenticate the security paper and prevent or deter counterfeiting.
A common type of security thread includes metal-formed characters or indicia disposed on a plastic carrier substrate. Such threads are coated with a layer of metal, such as aluminum, and display either: discrete metal characters as currently used in United States Currency; or negative or reverse-image characters as currently used in currencies such as the German Deutsche Mark. These threads are visually detectable in transmitted light by members of the public and are machine detectable by conventional thread detectors that detect the presence or absence of conductive features on the threads.
It has long been recognized that while visually detectable or public security features are both necessary and desirable, the use of non-apparent and/or concealed, machine testable security features offer a heightened level of security. If a counterfeiter does not recognize that a particular security feature is present within a document, attempts would not be made to reproduce that feature.
Several attempts have been made to combine multiple security detection features, such as metallic and magnetic features, to make counterfeiting more difficult. In one example, magnetic ink is used to print graphic indicia that can be read by MICR detectors. However, if magnetic ink is used to print graphic indicia on or with metallic security detection features, the magnetic features and metallic features are easily distinguishable and identified. A counterfeiter could recognize that both magnetic and metallic security detection features have been used and need to be reproduced.
Accordingly, a need exists for a security device that offers a heightened level of security.
It is, therefore, an object of the present invention to provide such a security device.
It is a more particular object to provide a security device having multiple security detection features, such as metal and metal/magnetic security detection features, some of which are not easily distinguishable and recognizable upon observing the security device.